The precision implant 9000 beam line

Abstract

The Precision Implant 9000 Ion Implanter employs a mass analysis geometry where the ribbon beam extracted from a Freeman type ion source has the long axis of the ion source extraction slot in the dispersion plane of the magnetic analysis system. This allows the ion source and its associated extraction system to be placed close to the analysing magnet. This means that the length of the extraction slot no longer determines the pole gap necessary for the analysing magnet as would be the case for conventional isotope separator optics. This geometry allows extraction from a long and wide extraction slot or multiple extraction slots. In the latter case each beam sees the same dispersion plane geometry. The above features, together with an extraction system employing a generous acceleration/deceleration ratio results in a system which will deliver high beam currents from a compact beam line with particularly advantageous extraction gap electrical breakdown characteristics. The design of the mass analysis system incorporates a number of features aimed at minimising cross-contamination caused by sputtering. The postacceleration system incorporates a five gap acceleration geometry which gives the flexibility necessary to provide the wide beam energy and current capability. The dosimetry system uses both electrostatic and magnetic suppression.